The present invention relates to door opening devices and, in particular, to a device to be used in conjunction with a door opener to overcome the resistance occurring when a door is moved between the closed position and the ajar position.
In my prior U.S. Pat. No. 5,634,296 I disclosed a device which can be connected between a door and a wall for opening and closing the door against an opening in the wall. Although this device will reliably move a door between and open position and a closed position, the device does not satisfactorily solve two problems which may occur when the device is attached to a typical door. First, where the door has a latch assembly, including a rotatable doorknob, the door must also be fitted with some form of latch release. The most commonly known latch release is the type found in apartment buildings which permits the occupants of apartments to electronically release a latched door by releasing the latch plate in the wall.
Another problem not adequately solved by the door opener in my prior U.S. Pat. No. 5,634,296 is the resistance incurred in moving a door between an ajar position and a closed position. When a door is moved between an ajar position to a fully open position, a door opening device such as disclosed in my prior patent need only overcome the resistance provided by the hinges retaining the door to the wall, and the resistance of the air disturbed by the movement of the door. The closing of a door from an open position to an ajar position also requires relatively little force. A much greater force may be required, however, to move the door between an ajar position and a closed position. An outer door, for example, has seals to prevent the leakage of air into or out of the enclosed premises and the seals cause added resistance during only the portion of the swing of the door between the ajar position and the closed position. The closing of a door against a door latch will also cause greater resistance in this small portion of the swing of the door.
A door controlling device in accordance with my prior patent could be fitted with a motor and a linkage sufficiently powerful to overcome all the forces incurred to fully open or fully close a door, but such a device would encounter another problem. The door controller of my prior patent includes an obstruction sensing device for terminating the operation thereof when the door encounters an object such as a chair or a person""s hand. When the door operator is fitted on a door which incurs a great deal of resistance in moving between the ajar and closed positions, the obstruction sensing device must not be so sensitive as to be triggered during this portion of an opening or closing cycle. It would, therefore, be desirable to provide a device which would be used in conjunction with a door opener such as disclosed in my prior U.S. Pat. No. 5,634,296 which would apply additional force at the end of a door closing cycle to move the door between the ajar position and the closed position, and provide additional force at the beginning of the door open cycle to move the door between the door closed position and an ajar position.
Briefly, the present invention is an assist to be used in conjunction with a motorized door operating device to assist in the opening of a door during its movement from the closed position to an ajar position, and to assist in the closing of the door during its movement from an ajar position to a closed position. The assist includes a connector mounted on one of the door and the wall and a moveable means mounted on the other of the door and wall for engaging and releasing the connector. During a door closing cycle, the assist remains inactive until the moveable means engages the connector, after which the moveable means moves in a first direction relative to the door or the wall to which it is attached. Movement of the moveable means in the first direction will move the door from the ajar position to a closed position. Upon the commencement of a door opening cycle, and upon completion of any unlatching cycle whereby any door latch retaining the door is released, the moveable means is moved in a second direction for moving the door from a closed position to an ajar position. Once the door is in the ajar position, the moveable means is disengaged from the connector and the door is allowed to move through the remainder of the door opening cycle without interference from the device.
In the preferred embodiment the assist includes a first detector for detecting when the moveable means has engaged with the connector during a closing cycle such that the moveable means will not commence its movement until the parts are in engagement. The assist further includes second and third detectors for detecting when the moveable means has reached the end of its travel in either the first direction or the second direction for terminating power to the motor upon completion of a cycle.
For a door which does not require the turning of a knob to release a latch, an opening cycle may be commenced simultaneously with the commencement of a door opening cycle of a door opener such as disclosed in my prior patent. A closing cycle is commenced when the first detector detects that the moveable means has engaged the connector.